Method and device for determining available capacity of battery, management system, and storage medium

ABSTRACT

A method and device for determining an available capacity of a battery, a battery management system, and a storage medium, relating to the field of battery technologies. The method includes: obtaining the at least one DOD interval corresponding to the SOC interval of the operation of the battery, and the number of cycles and the cycle temperature corresponding to the at least one DOD interval; obtaining a recoverable amount of capacity fade of the battery according to the at least one DOD interval, the number of cycles and the cycle temperature, and determining an actual available capacity of the battery.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application. Ser. No.16/857,135, filed Apr. 23, 2020, which claims priority to Chinese PatentApplication No. 201910338512.1, filed Apr. 25, 2019. Each of theseapplications is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to the field of battery technologies, andin particular, to a method and device for determining an availablecapacity of a battery, a battery management system, and a storagemedium.

BACKGROUND

The capacity of a battery refers to the amount of power stored in thebattery, and accurate estimation of the available capacity of thebattery is of great importance to the estimation of residual capacityand residual energy, etc., and is also an important parameter forreflecting an aging state of the battery cell Currently, the method ofestimating the available capacity of the battery generally comprises: anoffline capacity test to obtain a real capacity, wherein the availablecapacity of the battery is updated according to a calibrated agingcurve, or is online updated according to an open-circuit voltage and anSOC-OCV (open-circuit voltage) curve. However, some batteries sufferfrom two types of capacity fade: unrecoverable capacity fade andrecoverable capacity fade (like a memory effect). At present, the methodof estimating the available capacity of the battery cell can onlycalculate a sum of the two types of capacity fade, and cannot accuratelyobtain the available capacity of the battery.

SUMMARY

In view of the above, a technical problem to be solved by the presentdisclosure is to provide a method and device for determining anavailable capacity of a battery, a battery management system, and astorage medium.

According to an aspect of the present disclosure, there is provided amethod for determining an available capacity of a battery, comprising:obtaining an SOC interval corresponding to an operation of the battery,and determining at least one DOD interval corresponding to the SOCinterval; obtaining a number of cycles and a cycle temperaturecorresponding to the at least one DOD interval; obtaining a recoverableamount of capacity fade of the battery according to the at least one DODinterval, the number of cycles and the cycle temperature; anddetermining an actual available capacity of the battery based on therecoverable amount of capacity fade.

Alternatively, determining at least one DOD interval corresponding tothe SOC interval of the operation of the battery comprises: acquiringsetting information for setting the at least one DOD interval in an SOCusage interval corresponding to the battery; and determining the atleast one DOD interval corresponding to the SOC interval based on thesetting information.

Alternatively, obtaining a recoverable amount of capacity fade of thebattery according to the at least one DOD interval, the number ofcycles, and the cycle temperature comprises: pre-establishingcorrespondence information between the recoverable amount of capacityfade, the at least one DOD interval, the number of cycles and the cycletemperature; and obtaining the recoverable amount of capacity fadecorresponding to the at least one DOD interval, the number of cycles andthe cycle temperature based on the correspondence information.

Alternatively, the method further comprises: determining the SOCinterval based on a first SOC of the battery before the battery ischarged and a second SOC of the battery after the battery is charged;obtaining at least one DOD interval corresponding to the SOC interval,and obtaining the number of cycles and the cycle temperaturecorresponding to each DOD interval; obtaining an interval recoverableamount of capacity fade corresponding to each DOD interval based on thecorrespondence information and according to the at least one DODinterval, the number of cycles and the cycle temperature; obtaining afirst single recoverable amount of capacity fade of the battery in thecurrent operation based on at least one of the interval recoverableamount of capacity fade; and obtaining the recoverable amount ofcapacity fade of the battery under the current operating conditionaccording to the first single recoverable amount of capacity fade.

Alternatively, obtaining the recoverable amount of capacity fade of thebattery under the current operating condition according to the firstsingle recoverable amount of capacity fade comprises: obtaining one ormore second single recoverable amount of capacity fade corresponding toone or more previous operations of the battery; and processing the oneor more second single recoverable amount of capacity fade and the firstsingle recoverable amount of capacity fade according to a preset firstcalculation rule, to obtain the recoverable amount of capacity fade ofthe battery under the current operating condition.

Alternatively, the method further comprises: obtaining a second singlerecoverable amount of capacity fade corresponding to a last operation ofthe battery; obtaining two weight values corresponding to the secondsingle recoverable amount of capacity fade and the first singlerecoverable amount of capacity fade, and performing a weightedcalculation on the second single recoverable amount of capacity fade andthe first single recoverable amount of capacity fade based on the twoweight values to obtain the recoverable amount of capacity fade of thebattery under the current operating condition.

Alternatively, the method further comprises: obtaining a plurality ofSOC intervals corresponding to multiple cycles of the battery; obtaininga plurality of DOD intervals corresponding to the plurality of SOCintervals, and obtaining the number of cycles and the cycle temperaturecorresponding to each DOD interval; obtaining a plurality of intervalrecoverable amounts of capacity fade corresponding to the plurality ofDOD intervals based on the correspondence information and according tothe DOD intervals, the number of cycles and the cycle temperature; andobtaining the recoverable amount of capacity fade of the battery underthe current operating condition according to the plurality of intervalrecoverable amounts of capacity fade.

Alternatively, obtaining the recoverable amount of capacity fade of thebattery under the current operating condition according to the pluralityof interval recoverable amounts of capacity fade comprises: obtaining aninterval recoverable amount of capacity fade corresponding to each SOCinterval from the plurality of interval recoverable amounts of capacityfade; obtaining an accumulated recoverable amount of capacity fadecorresponding to each SOC interval based on the interval recoverableamount of capacity fade corresponding to each SOC interval; andprocessing a plurality of accumulated recoverable amounts of capacityfade corresponding to the plurality of SOC intervals according to apreset second calculation rule, to obtain the recoverable amount ofcapacity fade of the battery under the current operating condition.

Alternatively, processing a plurality of accumulated recoverable amountsof capacity fade corresponding to the plurality of SOC intervalsaccording to a preset second calculation rule, to obtain the recoverableamount of capacity fade of the battery under the current operatingcondition, comprises: obtaining a plurality of weight valuescorresponding to the plurality of accumulated recoverable amounts ofcapacity fade, and performing weighted calculation on the plurality ofaccumulated recoverable amounts of capacity fade based on the pluralityof weight values, to obtain the recoverable amount of capacity fade ofthe battery under the current operating condition.

Alternatively, determining an actual available capacity of the batterybased on the recoverable amount of capacity fade comprises: obtaining afirst available capacity of the battery based on battery operation data;calculating the actual available capacity of the battery based on thefirst available capacity and the recoverable amount of capacity fade,and obtaining a state of health of the battery based on the actualavailable capacity.

Alternatively, under the condition that the recoverable amount ofcapacity fade is greater than or equal to a preset threshold, it isdetermined that the recoverable amount of capacity fade of the batteryneeds to be eliminated and an operation is made accordingly.

Alternatively, the method further comprises: determining a number oftimes of charging and discharging, and performing a full charge and fulldischarge cycle operation on the battery according to the number oftimes of charging and discharging, to eliminate the recoverable amountof capacity fade of the battery.

According to another aspect of the present disclosure, there is provideda device for determining an available capacity of a battery, comprising:an information obtaining module, for obtaining an SOC intervalcorresponding to an operation of the battery, determining at least oneDOD interval corresponding to the SOC interval; and obtaining a numberof cycles and a cycle temperature corresponding to the at least one DODinterval; a recoverable capacity obtaining module, for obtaining arecoverable amount of capacity fade of the battery according to the atleast one DOD interval, the number of cycles and the cycle temperature;an available capacity correcting module, for determining an actualavailable capacity of the battery based on the recoverable amount ofcapacity fade; and a recoverable capacity processing module, fordetermining that the recoverable amount of capacity fade of the batteryneeds to be eliminated and an operation is made accordingly under thecondition that the recoverable amount of capacity fade is greater thanor equal to a preset threshold.

According to a still another aspect of the present disclosure, there isprovided a battery management system comprising: the device fordetermining an available capacity of a battery as described above.

According to a further aspect of the present disclosure, there isprovided a computer readable storage medium having stored thereoncomputer instructions, which, when executed by a processor, perform themethod as described above.

The method and device for determining an available capacity of abattery, the battery management system and the storage medium accordingto the present disclosure obtain at least one DOD interval correspondingto an SOC interval of an operation of the battery, and a number ofcycles and a cycle temperature corresponding to the at least one DODinterval; obtain a recoverable amount of capacity fade of the batteryaccording to the at least one DOD interval, the number of cycles and thecycle temperature; and determine an actual available capacity of thebattery. With respect to the battery with the recoverable amount ofattenuation capacity, the accuracy of estimating the actual availablecapacity and the SOH is improved, and the real aging state of thebattery can be accurately estimated, which can improve reliability ofthe battery and prolong the service life of the battery.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the embodiments of the presentdisclosure or the technical solutions in the prior art, the drawingsrequired for describing the embodiments or the prior art will be brieflydiscussed below, and it is obvious that the drawings in the followingdescription are merely some embodiments of the present disclosure, andthat other drawings can be obtained by those skilled in the art withoutpaying out any creative efforts.

FIG. 1 is a schematic flow chart of one embodiment of a method fordetermining an available capacity of a battery according to the presentdisclosure;

FIG. 2 is a schematic flow chart illustrating obtaining a recoverableamount of capacity fade in one embodiment of a method for determining anavailable capacity of a battery according to the present disclosure;

FIG. 3 is a schematic flow chart illustrating obtaining a recoverableamount of capacity fade in another embodiment of a method fordetermining an available capacity of a battery according to the presentdisclosure;

FIG. 4 is a schematic flow chart illustrating obtaining a recoverableamount of capacity fade in yet another embodiment of a method fordetermining an available capacity of a battery according to the presentdisclosure;

FIG. 5 is a schematic block diagram of one embodiment of a device fordetermining an available capacity of battery according to the presentdisclosure;

FIG. 6 is a schematic block diagram illustrating an informationobtaining module in one embodiment of a device for determining anavailable capacity of a battery according to the present disclosure;

FIG. 7 is a schematic block diagram illustrating a recoverable capacityobtaining module in one embodiment of a device for determining anavailable capacity of a battery according to the present disclosure;

FIG. 8 is a schematic block diagram illustrating a recoverableattenuation obtaining unit in one embodiment of a device for determiningan available capacity of a battery according to the present disclosure;

FIG. 9 is a schematic block diagram of another embodiment of a devicefor determining an available capacity of battery according to thepresent disclosure.

DETAILED DESCRIPTION

The present disclosure will be described more comprehensively below withreference to the accompanying drawings, in which exemplary embodimentsof the present disclosure are shown. The technical solutions in theembodiments of the present disclosure will be clearly and completelydescribed below with reference to the drawings in the embodiments of thepresent disclosure, and it is apparent that the described embodimentsare merely some embodiments of the present disclosure, but not allembodiments. All other embodiments, which can be derived by a person ofordinary skill in the art based on the embodiments in the presentdisclosure without creative efforts, are within the scope of protectionof the present disclosure. Aspects of the technical solutions of thepresent disclosure are described below in conjunction with variousfigures and embodiments.

The terms “first”, “second”, and the like, hereinafter, are used fordescriptive distinction only, but do not have other special meanings.

FIG. 1 is a schematic flow chart of one embodiment of a method fordetermining an available capacity of a battery according to the presentdisclosure, which as shown in FIG. 1 , comprises a step 101, ofobtaining an SOC (State of Charge) interval corresponding to anoperation of the battery, and determining at least one DOD intervalcorresponding to the SOC interval.

The battery may be a single battery cell, a battery pack, a batterymodule, etc. having a recoverable fade capacity, for example, thebattery may be a lithium battery, a lithium battery pack, etc. Theoperation of the battery refers to the charging/discharging cycleoperation of battery, and the DOD (depth of discharge) interval refersto an SOC operation interval set in an SOC usage interval correspondingto the battery. When the battery is charged or discharged, the SOCoperation interval corresponding to the charging or discharging of thebattery may be determined, and the at least one DOD intervalcorresponding to the SOC interval may be determined.

For example, the SOC usage interval corresponding to the battery is 0 to100%, and five DOD intervals are set in the SOC usage interval, wherethe five DOD intervals are 0 to 20%, 20 to 40%, 40 to 60%, 60 to 80%,and 80 to 100%, respectively. If the battery is discharged once, the SOCinterval corresponding to the discharging of the battery at this time is80-20%, then the SOC interval of 80-20% corresponds to three DODintervals, namely 20-40% DOD interval, 40-60% DOD interval and 60-80%DOD interval.

The method further comprises a step 102, of obtaining a number of cyclesand a cycle temperature corresponding to the at least one DOD interval.

The number of cycles is a number of cycle operations of the battery inthe at least one DOD interval. For example, the number of cyclescorresponding to the at least one DOD interval of 20 to 40% is a numberof cycles of charging and discharging of the battery in the at least oneDOD interval of 20 to 40%. The cycle temperature is a batterytemperature at which the battery operate in the at least one DODinterval. For example, the cycle temperature corresponding to the atleast one DOD interval of 20 to 40% is the temperature of the battery inthe at least one DOD interval of 20 to 40% in this operation.

The method further comprises a step 103, of obtaining a recoverableamount of capacity fade of the battery according to the at least one DODinterval, the number of cycles and the cycle temperature.

There may be various ways to obtain the recoverable amount of capacityfade of the battery according to the at least one DOD interval, thenumber of cycles, and the cycle temperature. For example, the magnitudeof the recoverable amount of capacity fade can be obtained throughexperiments, a correspondence between the magnitude of the recoverableamount of capacity fade and the at least one DOD interval, the number ofcycles, and the cycle temperature is established, and the recoverableamount of capacity fade can be obtained based on the correspondence.

The method further comprises a step 104, of determining an actualavailable capacity of the battery based on the recoverable amount ofcapacity fade.

The battery may have unrecoverable capacity fade and recoverablecapacity fade in the charging and discharging process, wherein theunrecoverable capacity fade is an unavailable capacity caused by theaging of the battery cell of the battery, and the recoverable capacityfade is a capacity which can be released again by the battery cell ofthe battery after a certain regulation in the cycling operation thereof,and this capacity cannot reflect the aging state of the battery cell.Due to the recoverable capacity fade, the real aging condition of thecurrent battery cell will be possibly overestimated, and therefore, theactual available capacity of the battery needs to be corrected by usingthe recoverable amount of capacity fade, and the actual availablecapacity of the battery is the real available capacity of the battery.

In one embodiment, there may be a number of ways to obtain the at leastone DOD interval corresponding to the SOC interval of the operation ofthe battery. For example, setting information for setting the at leastone DOD interval in the SOC usage interval corresponding to the batteryis acquired, and the at least one DOD interval corresponding to the SOCinterval is determined based on the setting information.

For example, the setting information for setting the at least one DODinterval in the SOC usage interval corresponding to the battery isinformation on five DOD intervals, which are 0 to 20%, 20 to 40%, 40 to60%, 60 to 80%, and 80 to 100%, respectively. Based on the settinginformation, the at least one DOD interval corresponding to the SOCinterval of 20 to 60% is determined to be the at least one DOD intervalof 20 to 40% and the at least one DOD interval of 40 to 60%.

FIG. 2 is a schematic flow chart illustrating obtaining a recoverableamount of capacity fade in one embodiment of a method for determining anavailable capacity of a battery according to the present disclosure,which as shown in FIG. 2 , comprises:

a step 201, of pre-establishing correspondence information between therecoverable amount of capacity fade and the at least one DOD interval,the number of cycles, and the cycle temperature.

The correspondence information between the recoverable amount ofcapacity fade and the at least one DOD interval, the number of cycles,and the cycle temperature can be established through experimental data,and the correspondence information comprises a functional relation, atable, a model and the like.

The method further comprises a step 202, of obtaining the recoverableamount of capacity fade corresponding to the at least one DOD interval,the number of cycles, and the cycle temperature based on thecorrespondence information.

The recoverable amount of capacity fade corresponding to different DODintervals, different numbers of cycles and different cycle temperaturesis calibrated through offline experiments. A operating condition cycletest is performed offline on the battery with a recoverable capacityfade characteristic, to test the recoverable amount of capacity fadecorresponding to different DOD intervals, different numbers of cyclesand different cycle temperatures. The recoverable amount of capacityfade of the battery cell of the battery can be obtained through variouscapacity test flows.

For example, the capacity of the battery cell is tested during thecapacity test of the battery cell, and the available capacity of thebattery cell without the recoverable amount of capacity fade underseveral full charge and full discharge cycles is counted; the batterycells and the battery cell parallel samples are circularly used indifferent DOD intervals and under different cycle temperatureconditions, and charge and discharge capacities of part of the batterycells are detected after several cycles; the other battery cellscontinue to circulate, and the charge and discharge capacities of thebattery cells after N cycles are measured; and finally, the availablecapacity of the battery cell without the recoverable amount of capacityfade under the current condition is counted through the capacity test ofthe battery cell and the full charge and full discharge cycles.

The correspondence functional relation or table correspondence etc.between the recoverable amount of capacity fade and the at least one DODinterval, the number of cycles and the cycle temperature isstatistically analyzed. For example, a correspondence table between therecoverable amount of capacity fade and the at least one DOD interval,the number of cycles, and the cycle temperature is established as shownin Table 1 below:

TABLE 1 correspondence table between the recoverable amount of capacityfade and the at least one DOD interval and the number of cycles at T1Recoverable amount of capacity fade N1 N2 . . . NX [S1, S2] D1 D2 . . .DX . . . . . . . . . . . . . . . [SA, SB] D1A D1B . . . D1X

In the Table 1, T1 is the cycle temperature, N1, N2, . . . , NXrepresent different numbers of cycles, [S1, S2], . . . , [SA, SB]represent different DOD intervals, D1, . . . , D1X in the Table 1represent the interval recoverable amount of capacity fade of thebattery under different operating conditions, D1, . . . , D1X can bepositive or negative, and D1, . . . , D1X can be obtained throughrelevant tests, experiments and the like.

The correspondence between the recoverable amount of capacity fade andthe at least one DOD interval, the number of cycles, and the cycletemperature may also include tables under a plurality of differenttemperature dimensions. For example, a plurality of cycle temperaturessuch as T2, T3, T4 are set for a certain battery, and related tests andexperiments are made, to obtain a plurality of tables for correspondencebetween the recoverable amount of capacity fade and the at least one DODinterval, the number of cycles at a plurality of cycle temperatures suchas T2, T3, T4, and the content of each table is shown in Table 1.

In one embodiment, if the SOC interval cannot correspond to a pluralityof complete DOD intervals, for example, a 30-40% interval in the SOCinterval of 30-60% corresponds to the at least one DOD interval of20-40%, the number of cycles and the cycle temperature corresponding tothe at least one DOD interval of 20-40% in the operation of the batteryat this time are determined, a corresponding coefficient is set, andwhen the recoverable amount of capacity fade is calculated, thecoefficient is multiplied by the interval recoverable amount of capacityfade corresponding to the at least one DOD interval of 20-40%, thenumber of cycles, and the cycle temperature. Similarly, if the cycletemperature is located between TI and T2, the cycle temperature may bedetermined as T1 and a corresponding coefficient may be set, and theinterval recoverable amount of capacity fade at T1 may be multiplied bythis coefficient when the recoverable energy information is obtained.

Besides the way of table, the correspondence between the recoverableamount of capacity fade and the at least one DOD interval, the number ofcycles and the cycle temperature can also be obtained through functionfitting to obtain a functional relation, and a regression equation or aneural network method and the like can be adopted.

FIG. 3 is a schematic diagram illustrating obtaining a recoverableamount of capacity fade in another embodiment of a method fordetermining an available capacity of a battery according to the presentdisclosure, which as shown in FIG. 3 , comprises:

a step 301, of determining the SOC interval based on a first SOC of thebattery before the battery is charged and a second SOC of the batteryafter the battery is charged;

a step 302, of obtaining at least one DOD interval corresponding to theSOC interval, and obtaining the number of cycles and the cycletemperature corresponding to each DOD interval;

a step 303, of obtaining an interval recoverable amount of capacity fadecorresponding to each DOD interval based on the correspondenceinformation and according to the at least one DOD interval, the numberof cycles and the cycle temperature;

a step 304, of obtaining a first single recoverable amount of capacityfade of the battery in the current operation based on at least oneinterval recoverable amount of capacity fade.

For example, it may be obtained that the SOC interval for batterycharging is a first SOC to a second SOC, a plurality of DOD intervalscorresponding to the SOC interval may be obtained, and the number ofcycles and the cycle temperature corresponding to each DOD interval maybe obtained. The interval recoverable amount of capacity fadecorresponding to each DOD interval can be obtained by table lookup or afunctional relation and according to the at least one DOD interval, thenumber of cycles and the cycle temperature. The obtained plurality ofinterval recoverable amounts of capacity fade are added to obtain afirst single recoverable amount of capacity fade of the battery in thecurrent operation.

The method further comprises a step 305, of obtaining the recoverableamount of capacity fade of the battery under the current operatingcondition according to the first single recoverable amount of capacityfade.

There may be various ways to obtain the recoverable amount of capacityfade of the battery under the current operating condition according tothe first single recoverable amount of capacity fade. For example, oneor more second single recoverable amount of capacity fade correspondingto one or more previous operation of the battery is obtained, and theone or more second single recoverable amount of capacity fade and thefirst single recoverable amount of capacity fade are processed accordingto a preset first calculation rule, to obtain the recoverable amount ofcapacity fade of the battery under the current operating condition.

There may be various first calculation rules, comprising a weightedcalculation rule or the like. For example, a second single recoverableamount of capacity fade corresponding to the last operation of thebattery is obtained, two weight values corresponding to the secondsingle recoverable amount of capacity fade and the first singlerecoverable amount of capacity fade are obtained, and a weightedcalculation is performed on the second single recoverable amount ofcapacity fade and the first single recoverable amount of capacity fadebased on the two weight values, so as to obtain the recoverable amountof capacity fade of the battery under the current operating condition.

In one embodiment, the SOC value of the battery before each charging andthe SOC value after the charging are recorded, an SOC interval isobtained, at least one DOD interval corresponding to the SOC interval isobtained, and the number of cycles and the cycle temperaturecorresponding to the at least one DOD interval are obtained. The firstsingle recoverable amount of capacity fade in the current operation ofthe battery is calculated through table lookup or a functional relation,and a plurality of second single recoverable amounts of capacity fadecorresponding to a plurality of previous operations of the battery arecalculated based on a first calculation rule to obtain the recoverableamount of capacity fade of the battery under the current operatingcondition.

For example, a second single recoverable amount D1 of capacity fadecorresponding to the last charging of the battery is acquired, and afirst single recoverable amount D2 of capacity fade corresponding to thecurrent operation of the battery is obtained, then the recoverableamount of capacity fade of the battery under the current operatingcondition is Dnew=α₁D₁+α₂D₂, where α₁ and α₂ are weight values (weightcoefficients) and a numerical range of α₁ and α₂ is [−1, 1]. Therecoverable amount of capacity fade of the battery can be updated afterthe battery is charged this time.

FIG. 4 is a schematic diagram illustrating obtaining a recoverableamount of capacity fade in yet another embodiment of a method fordetermining an available capacity of a battery according to the presentdisclosure, which as shown in FIG. 4 , comprises:

a step 401, of obtaining a plurality of SOC intervals corresponding tomultiple use cycles of the battery;

a step 402, of obtaining a plurality of DOD intervals corresponding tothe plurality of SOC intervals, and obtaining the number of cycles andthe cycle temperature corresponding to each DOD interval;

a step 403, of obtaining a plurality of interval recoverable amounts ofcapacity fade corresponding to the plurality of DOD intervals based onthe correspondence information and according to the DOD intervals, thenumber of cycles and the cycle temperature; and

a step 404, of obtaining the recoverable amount of capacity fade of thebattery under the current operating condition according to the pluralityof interval recoverable amounts of capacity fade.

There are various ways to obtain the recoverable amount of capacity fadeof the battery under the current operating condition according to theplurality of interval recoverable amounts of capacity fade. For example,the interval recoverable amount of capacity fade corresponding to eachSOC interval is obtained from the plurality of interval recoverableamounts of capacity fade, and an accumulated recoverable amount ofcapacity fade corresponding to each SOC interval is obtained based onthe interval recoverable amount of capacity fade corresponding to eachSOC interval. The plurality of accumulated recoverable amounts ofcapacity fade corresponding to the plurality of SOC intervals areprocessed according to a preset second calculation rule to obtain therecoverable amount of capacity fade of the battery under the currentoperating condition.

There may be various second calculation rules, comprising a weightedcalculation rule or the like. For example, a plurality of weight valuescorresponding to the plurality of accumulated recoverable amounts ofcapacity fade are obtained, and a weighted calculated is performed onthe plurality of accumulated recoverable amounts of capacity fade basedon the plurality of weight values to obtain the recoverable amount ofcapacity fade of the battery under the current operating condition.

In one embodiment, a plurality of SOC intervals corresponding to aplurality of charging cycles of the battery are obtained, a plurality ofDOD intervals corresponding to the plurality of SOC intervals areobtained, and a number of cycles and cycle temperatures corresponding toeach DOD interval are obtained. A plurality of interval recoverableamounts of capacity fade corresponding to the plurality of SOC intervalsof the operation of the battery are obtained according to the tablelookup or the functional relation and according to the DOD intervals,the number of cycles and the cycle temperature.

An accumulated recoverable amount of capacity fade corresponding to theplurality of SOC intervals of the operation of the battery are obtainedbased on the interval recoverable amounts of capacity fade correspondingto the plurality of SOC intervals of the operation of the battery,respectively. For example, the interval recoverable amounts of capacityfade corresponding to each SOC interval are added to obtain theaccumulated recoverable amount of capacity fade corresponding to eachSOC interval. A plurality of accumulated recoverable amounts of capacityfade corresponding to the plurality of SOC intervals are calculated toobtain the recoverable amount of capacity fade of the battery under thecurrent operating condition.

For example, the plurality of accumulated recoverable amounts ofcapacity fade corresponding to the plurality of SOC intervals are D1,D2, . . . , DN, and the current recoverable amount of capacity fade ofthe battery is Dnew=α₁D₁+α₂D₂+ . . . +α_(n−1)D_(n−1)+α_(n)D_(n), whereα₁˜α_(n) are weight values (weight coefficients) and the numerical rangeis [−1, 1]. The recoverable amount of capacity fade of the battery isupdated after multiple cycles of operation of the battery.

In one embodiment, the currently measured capacity value is recordedwhen the operating state of the battery reaches a condition for batterycapacity estimation or when a battery capacity test is performed at aservice station. The condition for the battery capacity estimation maybe various conditions, e.g., the number of cycles of operation of thebattery reaches a threshold.

There may be various ways to determine the actual available capacity ofthe battery based on the recoverable amount of capacity fade. Forexample, a first available capacity of the battery is obtained based onthe battery operation data, the actual available capacity of the batteryis calculated from the first available capacity and the recoverableamount of capacity fade, and a state of health of the battery isobtained based on the actual available capacity. There may be variousways to obtain the first available capacity of the battery, for example,calculating the first available capacity of the battery by linearinterpolation of the accumulated ampere-hour value based on the batteryoperation data, and the like. The battery may have a recoverablecapacity fade part during charging and discharging, and the firstavailable capacity of the battery cannot reflect the aging state of thebattery cell, so the recoverable amount of capacity fade may be added tothe first available capacity of the battery to obtain the actualavailable capacity of the battery.

If the recoverable amount of capacity fade is greater than or equal to apreset threshold, it is determined that it is necessary to eliminate therecoverable amount of capacity fade of the battery and an operation ismade accordingly. The operation accordingly includes: determining thenumber of charge and discharge cycles, and performing a full charge andfull discharge cycle operation on the battery according to the number ofcharge and discharge cycles to eliminate the recoverable amount ofcapacity fade of the battery.

For example, when the recoverable amount of capacity fade or the amountof capacity fade reaches a preset threshold and this may affect the tripof the user, it is needed to prompt the user to maintain the battery orperform N full charge and full discharge cycles to eliminate therecoverable amount of capacity fade, where N is the number of charge anddischarge cycles required to eliminate the capacity fade under thecurrent recoverable amount of capacity fade measured by the experiments.

The State Of Health (SOH) is an important parameter reflecting theperformance and the service life of the battery, and the SOH is used forestimating a real aging state of the battery cell. The state of healthSOH of the battery often refers to a ratio of the capacity of the agedbattery to the capacity of a fresh battery cell. The battery isinevitably aged or deteriorated in a long-term use, so that the batterycapacity is notably reduced, and if the SOH is not corrected after thebattery capacity is attenuated, the calculation error of the State ofCharge (SOC) of the battery is possibly increased, and problems such asovercurrent risk and the like exist. There are a variety of ways toobtain the state of health of the battery based on the actual availablecapacity. For example, SOH of the battery=actual availablecapacity/nominal capacity value, wherein the nominal capacity value maybe a standard capacity value preset at the time of shipment.

In one embodiment, as shown in FIG. 5 , the present disclosure providesa device 50 for determining an available capacity of a battery,comprising: an information obtaining module 51, a recoverable capacityobtaining module 52, an available capacity correcting module 53, and arecoverable capacity processing module 54. The information obtainingmodule 51 is for obtaining an SOC interval corresponding to an operationof the battery, determining at least one DOD interval corresponding tothe SOC interval, and obtaining a number of cycles and a cycletemperature corresponding to the at least one DOD interval. Theinformation obtaining module 51 may acquire setting information forsetting the at least one DOD interval in the SOC usage intervalcorresponding to the battery, and determine the at least one DODinterval corresponding to the SOC interval based on the settinginformation. The recoverable capacity obtaining module 52 is forobtaining a recoverable amount of capacity fade of the battery accordingto the at least one DOD interval, the number of cycles and the cycletemperature. The available capacity correcting module 53 is fordetermining an actual available capacity of the battery based on therecoverable amount of capacity fade.

In one embodiment, as shown in FIG. 7 , the recoverable capacityobtaining module 52 comprises: a mapping information setting unit 521and a recoverable attenuation obtaining unit 522. The mappinginformation setting unit 521 pre-establishes correspondence informationbetween the recoverable amount of capacity fade and the at least one DODinterval, the number of cycles, and cycle temperature. The recoverableattenuation obtaining unit 522 obtains a recoverable amount of capacityfade corresponding to the at least one DOD interval, the number ofcycles, and the cycle temperature based on the correspondenceinformation.

As shown in FIG. 6 , the information obtaining module 51 comprises: afirst information determining unit 511 and a second informationdetermining unit 512. As shown in FIG. 8 , the recoverable attenuationobtaining unit 522 comprises: a first obtaining unit 523 and a secondobtaining unit 524.

The first information determination unit 511 determines the SOC intervalbased on a first SOC of the battery before charging and a second SOC ofthe battery after charging; obtains at least one DOD intervalcorresponding to the SOC interval, and obtains the number of cycles andthe cycle temperature corresponding to each DOD interval. The firstobtaining unit 523 obtains an interval recoverable amount of capacityfade corresponding to each DOD interval based on the correspondenceinformation and according to the at least one DOD interval, the numberof cycles and the cycle temperature. The first obtaining unit 523obtains a first single recoverable amount of capacity fade of thebattery in the current operation based on at least one intervalrecoverable amount of capacity fade, and obtains the recoverable amountof capacity fade of the battery under the current operating conditionaccording to the first single recoverable amount of capacity fade.

The first obtaining unit 523 obtains one or more second singlerecoverable amount of capacity fade corresponding to one or moreprevious operations of the battery; and processes the one or more secondsingle recoverable amount of capacity fade and the first singlerecoverable amount of capacity fade according to a preset firstcalculation rule, to obtain the recoverable amount of capacity fade ofthe battery under the current operating condition.

The first obtaining unit 523 obtains a second single recoverable amountof capacity fade corresponding to a last operation of the battery;obtains two weight values corresponding to the second single recoverableamount of capacity fade and the first single recoverable amount ofcapacity fade, and performs a weighted calculation on the second singlerecoverable amount of capacity fade and the first single recoverableamount of capacity fade based on the two weight values to obtain therecoverable amount of capacity fade of the battery under the currentoperating condition.

The second information determining unit 512 obtains a plurality of SOCintervals corresponding to multiple cycles of the battery; obtains aplurality of DOD intervals corresponding to the plurality of SOCintervals. The second information determining unit 512 obtains thenumber of cycles and the cycle temperature corresponding to each DODinterval. The second obtaining unit 524 obtains a plurality of intervalrecoverable amounts of capacity fade corresponding to the plurality ofDOD intervals based on the correspondence information and according tothe DOD intervals, the number of cycles and the cycle temperature. Thesecond obtaining unit 524 obtains the recoverable amount of capacityfade of the battery under the current operating condition according tothe plurality of interval recoverable amounts of capacity fade.

The second obtaining unit 524 obtains an interval recoverable amount ofcapacity fade corresponding to each SOC interval from the plurality ofinterval recoverable amounts of capacity fade. The second obtaining unit524 obtains an accumulated recoverable amount of capacity fadecorresponding to each SOC interval based on the interval recoverableamount of capacity fade corresponding to each SOC interval; andprocesses a plurality of accumulated recoverable amounts of capacityfade corresponding to the plurality of SOC intervals according to apreset second calculation rule, to obtain the recoverable amount ofcapacity fade of the battery under the current operating condition.

The second obtaining unit 524 obtains a plurality of weight valuescorresponding to the plurality of accumulated recoverable amounts ofcapacity fade, and performs weighted calculation on the plurality ofaccumulated recoverable amounts of capacity fade based on the pluralityof weight values, to obtain the recoverable amount of capacity fade ofthe battery under the current operating condition.

The available capacity correcting module 53 obtains a first availablecapacity of the battery based on battery operation data; calculates theactual available capacity of the battery based on the first availablecapacity and the recoverable amount of capacity fade, and obtains astate of health of the battery based on the actual available capacity.

If the recoverable amount of capacity fade is greater than or equal to apreset threshold, the recoverable capacity processing module 54determines that the recoverable amount of capacity fade of the batteryneeds to be eliminated and an operation is made accordingly. Therecoverable capacity processing module 54 determines a number of timesof charging and discharging, and performs a full charge and fulldischarge cycle operation on the battery according to the number oftimes of charging and discharging, to eliminate the recoverable amountof capacity fade of the battery.

FIG. 9 is a block diagram of another embodiment of a device fordetermining an available capacity of a battery according to the presentdisclosure. As shown in FIG. 9 , the device may comprise a memory 91, aprocessor 92, a communication interface 93, and a bus 94. The memory 91is for storing instructions and the processor 92 is coupled to thememory 91, and the processor 92 is configured to perform theabove-described method for determining an available capacity of abattery based on the instructions stored in the memory 91.

The memory 91 may be a high-speed RAM memory, a non-volatile memory, orthe like, and the memory 91 may be also a memory array. The memory 91may also be divided into blocks and the blocks may be combined intovirtual volumes according to certain rules. The processor 92 may be acentral processing unit CPU, or an Application Specific IntegratedCircuit (ASIC), or one or more Integrated circuits configured toimplement the method for determining an available capacity of a batteryaccording to the present disclosure.

In one embodiment, the present disclosure provides a battery managementsystem comprising the device for determining an available capacity of abattery as in any of the above embodiments. The battery managementsystem may be installed in a vehicle or the like, and may manage thebattery.

In one embodiment, the present disclosure provides a computer-readablestorage medium having stored thereon computer instructions that, whenexecuted by a processor, implement the method for determining anavailable capacity of a battery as in any one of the above embodiments.

The method and device for determining an available capacity of abattery, the battery management system and the storage medium in theabove embodiments obtain the at least one DOD interval corresponding tothe SOC interval of the operation of the battery, and the number ofcycles and the cycle temperature corresponding to the at least one DODinterval, obtain a recoverable amount of capacity fade of the batteryaccording to the at least one DOD interval, the number of cycles and thecycle temperature, and correct the available capacity of the battery.With respect to the battery with the recoverable amount of attenuationcapacity, the recoverable amount of capacity fade of the battery isobtained, the available capacity is estimated based on the recoverableamount of capacity fade, which improves the accuracy of estimating theactual available capacity and the SOH, can improve reliability of thebattery, and can prolong the service life of the battery and the useexperience of the user.

The method and system of the present disclosure may be implemented in anumber of ways. For example, the method and system of the presentdisclosure may be implemented by software, hardware, firmware, or anycombination of software, hardware, and firmware. The above-describedorder of the steps for the method is for illustration only, and thesteps of the method of the present disclosure are not limited to theorder specifically described above unless specifically stated otherwise.Further, in some embodiments, the present disclosure may also beembodied as programs recorded in a recording medium, the programsincluding machine-readable instructions for implementing the methodaccording to the present disclosure. Thus, the present disclosure alsocovers a recording medium storing a program for executing the methodaccording to the present disclosure.

The description of the present disclosure has been presented forpurposes of illustration and description, and is not intended to beexhaustive or limited to the disclosure in the form disclosed. Manymodifications and variations will be apparent to those of ordinary skillin the art. The embodiments were chosen and described in order to bestexplain the principles of the disclosure and the practical applicationthereof, and to enable those of ordinary skill in the art to understandthe present disclosure and thus design various embodiments with variousmodifications as are suited to particular uses.

What is claimed is:
 1. A method for determining an available capacity ofa battery, comprising: determining a State of Charge (SOC) interval ofthe battery based on a first SOC of the battery before the battery ischarged and a second SOC of the battery after the battery is charged;determining at least one Depth of Discharge (DOD) interval set in theSOC interval based on setting information, wherein the DOD interval isan SOC operation interval set in an SOC usage interval which is 0 to100%; determining a number of cycles and a cycle temperature of thebattery in the at least one DOD interval, wherein the number of cyclesis a number of cycle operations of the battery in one DOD interval, andwherein the cycle temperature is a battery temperature at which thebattery operates in one DOD interval; determining an intervalrecoverable amount of capacity fade of the battery based oncorrespondence information between an interval recoverable amount ofcapacity fade, and the at least one DOD interval, the number of cyclesand the cycle temperature in the at least one DOD interval, wherein thecorrespondence information is calibrated by performing an operatingcondition cycle test to test the recoverable amount of capacity fadecorresponding to different DOD intervals, different numbers of cyclesand different cycle temperatures, and wherein the correspondenceinformation comprises a functional relation, a table, or a model;determining a first single recoverable amount of capacity fade of thebattery in a current operation by adding a plurality of intervalrecoverable amounts of capacity fade; determining a second singlerecoverable amount of capacity fade of the battery in the lastoperation; determining the recoverable amount of capacity fade of thebattery under the current operating condition by performing a weightedcalculation on the second single recoverable amount of capacity fade andthe first single recoverable amount of capacity fade; and correcting anactual available capacity of the battery based on the recoverable amountof capacity fade of the battery.
 2. The method according to claim 1,wherein the recoverable amount of capacity fade of the battery under thecurrent operating condition is Dnew=α1D1+α2D2, where D1 is the secondsingle recoverable amount of capacity fade, D2 is the first singlerecoverable amount of capacity fade, α1 and α2 are weight values, and anumerical range of α1 and α2 is [−1, 1].
 3. The method according toclaim 1, wherein correcting an actual available capacity of the batterybased on the recoverable amount of capacity fade comprises: calculatinga first available capacity of the battery by linear interpolation of anaccumulated ampere-hour value based on battery operation data;calculating the actual available capacity of the battery by adding thefirst available capacity to the recoverable amount of capacity fade; andobtaining a state of health of the battery based on the actual availablecapacity.
 4. The method according to claim 1, further comprising: underthe condition that the recoverable amount of capacity fade is greaterthan or equal to a preset threshold, determining that the recoverableamount of capacity fade of the battery needs to be eliminated.
 5. Themethod according to claim 4, further comprising: under the conditionthat the recoverable amount of capacity fade is greater than or equal toa preset threshold, performing N full charge and full discharge cycleoperations on the battery to eliminate the recoverable amount ofcapacity attenuation of the battery, wherein N is the number of chargeand discharge cycles required to eliminate the capacity fade under thecurrent recoverable amount of capacity fade measured by the experiments.